Link an object from a different Blender file and be able to move it around while retaining its modifiers
Place the object in a group (fine for it to be a group of one) in the first file (the one with the object you want to link in) and link that group (instead of the object itself) in the second file.  You will be able to move the object around in the second file right away, the un-applied modifiers it had in the first file will still be there, and changes made to the object in the first file later will update in the second file.